Switch mechanism



June 17, 1941 .1. c. YlN-GLING SWITCH MBCHANISM Filed March 27, 1940 Patented June 17, 1941 UNITED STATES PATENT OFFICE (Granted under the act of March 3, 1883, as amended April 3Q, 1928; 370 0. G.. 357) 9 Claims.

The invention described herein may be manuiactured and used by or for the Government for governmental purposes, without the payment to me ci any royalty thereon.

This invention relates to pressure responsive itch mechanism for automatic pressure reguors.

Although broadly applicable as a switch operating mechanism, this invention is particularly applicable to a ballonet used in connection with an observation baloon. The ballonet is a. relatively smell air-filled balloon adapted to be placed internaily oi' a baloon filled with a. buoyant gas, such as helium. The ballonet obviates wasting oi' buoyant gas by being provided with a relief valve and an air compressor to maintain the pressure in the ballonet constant within certain limits in response to expansion and contraction of the buoyant gas in the balloon. When the balloon accende to a region of rareiled atmosphere or is subjected to a temperature increase, the buoyant ges expands, forcing air from the ballonet by way oi the relief valve. Upon descent of the balloon or a decrease in temperature resulting in contraction of the buoyant gas, the compressor automatically operates to maintain the air in the ballonet within the predetermined limits.

it is an obicet ci this invention to provide a compresser-operating switch which is sensitive to smell pressure changes, which is operated by a email force and yet which is positive in action.

It is a further object of this invention to provide a sensitive switch which positively stays in` either the make or break position.

It is a still further object oi this invention to utilize a coil spring as a snap spring for providing relative movement between the contact elements of a. switch.

Other objects of the invention will become apparent from the following description taken in connection with the accompanying drawing, in which:

Figure l is a sectional view through a-device incorporating the invention with some of the parts shown in elevation;

Figure 2 is a view similar to Figure 1 but showing the switch in open position;

Figure 3 is a cross-sectional view taken generally along the lines 3-3 of Figure 2; and

Figure 4 is a diagrammatic arrangement of the center line o! the spring in its various positions during operation o! the switch in one direction, the curves being somewhat accentuated ior purpose o! illustration.

Referring to the drawing:

Ballonet or container I has suitably connected thereto a disk 2 carrying a collar 3. A gastight connection is provided between container I and disk 2. Flexible member 5 sealingly connects collar 3 with diaphragm member 4, mounted to move up and down in response to the differential between the upward force exerted by spring 6 and the downward force resulting from air pressure on the upper side of the diaphragm member.

Movement of the diaphragm member actuates switch-operating mechanism constituting the primary-feature of this invention.

The switch is composed oi contact elements 25 and 2B. Pin 38 serves as a stop for resilient contact element 25 which in turn is fastened to plate I'I by bracket 23 and electrically connected by conductor wire 29 to connection 34 of commercial relay switch 35. Contact element 2E is carried by member 2li pivotally mounted by means of pin 2l on panel I1 and electrically connected by conductor wire 28 to connection 33 of the relay switch. In order that conductor wire 28 will have the least possible effect on the action of spring EE, it is made of extremely flexible material and may be arranged substantially along the center line established by pivots 2| and 24. Contacts 36 and 31 of the relay switch are connected to an outside source of electrical energy and a compressor mechanism (not shown) for maintaining the ballonet or container I filled with air at a predetermined pressure.

Contact between elements 25 and 26 is established and broken by cell spring I6, suitably connected to contact-element-carrying member 20 by looping an end of the spring wire about the pin 2l upon which member 20 is pivotally mounted. Member 20 is provided with a pro- Jecting portion 3l, receivable in the coil oi spring I6 for insuring concurrent movement of that end of the coil spring and member 20 and for a iurther purpose to be more fully explained hereinafter. The coil spring is similarly connected at its other end to pin 24, upon which slotted lever arm I2 is pivotally mounted. Arm I2 is provided with a projecting portion 32 corresponding to the projection 3| of member 2| Guide member 21 suitably fastened to plate I'I, connes the buckling movement of spring i6 to a vertical plane.

Arm I2 is slotted at 43 to receive stud pin I5, which in turn is suitably connected to cylindrical plug Il by being screwed thereinto. Tube I0 is slotted at 44 to permit relative slidable movement between pin I5 and the tube. Cylindrical plug Il is adjustably received and held in tube I0 by bolt lo threaded to correspond to the internal threads of member Relative longitudinal movement between bolt 40 and tube III is prevented by collar 4l, cylindrical member Il, and cap I4. Collar 4| is formed integral with bolt 40; member I3 is fastened to bolt 40 by cotter pin 42; and cap i4 is screwthreaded to tube I0. Bolt G is' freely rotatably length, size and stillness of wire, number of coils,

etc., is such that when the spring is attached to pivots 2| and 24 in the open position oi' the switch shown in Figure 2, it is necessary to com Dress it to the extent that it will assume the curved or arced position shown in Figure 2 with its center line as shown| by the curve A in Figure 4. Upward movement of the diaphragm member results in progressive exing of the spring to where its center line assumes the positions B, C and, finally, D oi' Figure 4. The spring may be said to bend into a sinuous form when being moved from one to the other side of dead center position. By use of projections 3| and 32, a relatively soft or flexible spring can be used, the center oi' which assumes a position sumciently far from the center line established by the pivot points 2| and 24 to maintain the spring in its extreme positions, regardless of jarring to which the device may be subjected. The pivot points 2| and 24 may be adjustabiy moimted and the lengths of projections 3| and 32 so selected as to give the desired throw to spring I6 in response to the available switch operating force resulting from a pressure change in member I. I'he lengths oi projections 3| and 32 together with the spacing oi' pivots 2| and 24 govern the transmission of the switch operative force from the diaphragm member to the pivotal contactelement and consequently the operative speed oi the switch. By use of this arrangement, a switch responsive to one-fourth inch of water pressure has been constructed.

The operation of the device is as follows: Plug -H is suitably adjusted to position the pin I5 in the center of the upper and lower limits of travel of tubular plunger I0, the center being established by a line through the center line of pins 2| and 24. A switch-carrying plate I1 is adjusted to suit, and the spring 6 compressed a desired amount by ring 8.

With the parts as shown in Figure 1, the switch being in closed compressor-operating position'. an increase in pressure causes movement of the spring from position A in Figure 4 through position B into position C. from which it snaps into switch-opening position D. A decrease in pressurein container i causes the spring to assume a position on the underside of the center line of pivotation corresponding to position B on the upper side, thence into a position corresponding to position C. and finally the spring snaps into switch-closing position A.

In the preferred embodiment oi the device, a coil spring is used because of its relatively large i'orce transmitting properties, soft action and controllable throw. In the broad application oi ments, one of which is pivotaily mounted, means for moving said pivotaily mounted contact element into and out of electrical contact with said other contact element including: an actuating means, a pivotaily mounted arm operatively connected to said actuating means to be pivoted thereby, a coil spring connected at one end to said arm and at the other end to said pivotaily :mounted contact element. said spring being of such length and exibility that when attached t0 said pivotal contact and arm, it buckles to an arced position on one side of dead center position established by the points of pivotation of said pivotal contact and arm, and means for confining the buckling of said spring to a given plane whereby operation of said actuating means iiexes said Spring from switch-opening position on one side of dead center position into and through a sinuous curve to an arced switch-closing position on the other'side of dead center position.

2. A device as recited in claim 1 in which said actuating means comprises reciprocal diaphragm means having a projecting pin integral therewith and in which said pivotaily mounted arm is slotted to receive said pin whereby reciprocation of said diaphragm means results in pivotation of said arm.

3. A device as recited in claim 1 in which said actuating means comprises reciprocal diaphragm means having a projecting pin integral therewith and in which said pivotaily mounted arm is slotted to receive said pin, and means for adjusting the position of said pin on said actuating means to vary the responsiveness of said switch to said actuating means.

4. In an automatic, pressure regulator, diaphragm means mounted to move in response to a. force diii'erential exerted thereon, a contact switch including a. pair of contact elements, one of which is pivotaily mounted. and means responsive to movement of said diaphragm means for moving said pivotaily mounted contact element to switch-opening and closing position includshape of an arc on one or the other side of dead center position, and means for preventing lateral movement of said spring whereby said spring will assume the form of a sinuous curve in a given piane during movement from one to theother side of dead center position in response to switchopening or closing movement of said diaphragm means.

5. In an automatic pressure regulator; diaphragm means mounted to move in response to pressure variation, a switch including a pivotaily mounted contact element, and means responsive to movement of said diaphragm means for operating said switch including: a pivotaily mounted lever arm connected to said diaphragm means for pivotal operation thereby, a coil spring connected at one end to said arm and atthe other end to said pivotally mounted contact element, saidspring being initially compressed and of such a length as to assume the shape of an arc on one or the other side of dead center position, and means for preventing lateral movement of said spring whereby 'said spring will assume a sinuous shape in a given plane during movement from one to the other side of dead center position.

6. A device as `recited in claim 5 varid further characterized by said pivotal arm and pivotal contact having projecting portions of a preselected length receivable in the ends of said coil spring.

7. A device as recited in claim 5 and further including a pin and slot connection between said diaphragm means and said lever arm.

8. A switch comprising a pair of contact elements, one of which is pivotally mounted, and means for moving said pivotally mounted contact element into and out of electrical connection with said other contact elementv including; a pivotally mounted arm, an initially compressed coil spring connected at one end to said pivotally mounted contact element and at the other end to said pivotally mounted arm, said spring beingI relatively long and of such characteristics that it will normally assume an arced position to one side of dead center position, and means for preventing lateral buckling of said spring whereby pivotation of said arm bends said spring into and through a sinuous curve in a given plane to an arced position on the other side of dead center position.

9. In an automatic pressure regulator, diaphragm means mounted to move in response to a force differential exerted thereon, a switch including a pair of contact elements, one of which is pivotally mounted'to move to make and break positions, a pvotally mounted arrri, an initially compressed coil spring connected at one end to said pivotally mounted kcontact. element and at .the other end to said pivotally mounted arm, said spring being of such a length as to normally lie in the shape of an arc on one or the other side of dead center position, means for preventing lateral movement of said spring, and means operatively connecting said arm to said diaphragm means including a pin carrying member integral with said diaphragm means, said arm being slotted to receive said pin, and means for adjusting said pin with respect to said member to vary the responsiveness of said switch to movement of said diaphragm means.

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